Germany have hit out at "under the belt" criticism of Mesut Ozil as the under-fire holders attempt to get their World Cup campaign back on track against Sweden.
Joachim Loew's team have faced a fierce backlash after their poor first-half display in the 1-0 defeat to Mexico on Sunday.
Attacking midfielder Ozil was singled out in some quarters, with ex-Germany captain Lothar Matthaeus accusing him of "no heart, no joy, no passion" in a woeful display.
"We have to live with the criticism after the Mexico defeat, the main body of which is justified," said team director Oliver Bierhoff at a press conference in Sochi on Wednesday.
"I just find it a pity that a few comments have gone under the belt, not just for Mesut Ozil, but in general.
"Hard criticism is OK, but malicious comments against deserving world champions are not."
Loew is under intense pressure to drop Ozil for the high-pressure second Group F game against Sweden on Saturday, where a second defeat would effectively send the Germans home.
Ozil arrived in Russia following an unimpressive season with Arsenal and Matthaeus believes he no longer deserves his place in the Germany team.
"Watching Ozil on the pitch, I often have the feeling that he doesn't feel comfortable in the German shirt," wrote Matthaeus in German daily Bild.
"It's almost as if he does not want to play at all. There is no heart, no joy, no passion. For a year or two, Ozil has played at a much weaker level, which does not justify his place in Loew's team."
In the run-up to the World Cup, Ozil, who was born in Gelsenkirchen to Turkish parents, controversially posed alongside Turkey's President Recep Tayyip Erdogan.
It sparked debate about his loyalty to Germany, drew heavy criticism from far-right political party Alternative for Germany (AfD) and he was booed in a pre-World Cup friendly.
Ozil has refused to comment on the controversy.
"He did not understand why there are such great discussions in Germany about him," Matthaeus added. "He is unaware of what people in Germany expect from a national player.
"It would have been right after the mistake of the Erdogan photo, to make a commitment to Germany, to open up to the fans."